Nabeel-Shah S, Ashraf K, Saettone A, Garg J, Derynck J, Lambert JP, Pearlman RE, Fillingham J (2020) Nucleus-specific linker histones Hho1 and Mlh1 form distinct protein interactions during growth, starvation and development in Tetrahymena thermophila. Scientific reports 10(1):168 PUBMED:31932604
Akematsu T, Sánchez-Fernández R, Kosta F, Holzer E, Loidl J (2019) The Transmembrane Protein Semi1 Positions Gamete Nuclei for Reciprocal Fertilization in Tetrahymena. iScience 23(1):100749 PUBMED:31884169
Tian M, Loidl J (2019) An MCM family protein promotes interhomolog recombination by preventing precocious intersister repair of meiotic DSBs. PLoS genetics 15(12):e1008514 PUBMED:31815942
Identifiers and Description
Gene Model Identifier
TTHERM_00590090
Standard Name
CMB1 (CalModulin-Binding 1)
Aliases
PreTt24124 | 81.m00181 | 3726.m00057
Description
Calmodulin-binding protein; roles in cytokinesis and phagocytosis; localizes to division furrow, oral apparatus, and crescent-shaped structure; binds G-actin but not F-actin; localization and protein modifications disrupted in mutant cdaA1
A recessive gene determining temperature-sensitive fission arrest was described in 1976 under the name "mo1". Around 1979, following the (then) new nomenclatural rules, it was re-named cdaA1 (CDA="cell division arrest"). In the early 1980's, Y. Watanabe and his associates made some remarkable findings reported in 1986. Using 2D-gel electrophoresis, they found a protein, which they called p85 (later renamed Cmb1p), which was localized to the oral apparatus and also to an apical filament ring and to structures (which turned out to be basal-body couplets) located just posterior to the division furrow. The equatorial localization was observed in cdaA1 homozygotes at the permissive temperature (when division took place), but not after a shift to the restrictive temperature (when the division furrow failed to develop). Based on these studies it was naturally assumed that p85 was the protein product of the cdaA gene, especially as p85 differed slightly in mobility in 2D-gels made from wild-type and cdaA1 cell extracts. However, in 1999 the gene encoding p85 was cloned. This yielded a big surprise: "The cdaA1 p85 cDNA contained one open reading frame and its deduced amino acid sequence, cdaA1 p85, was completely identical to that of wild-type p85" (p. 116). There were some differences in the 3'UTR and 5' UTRs, but they "do not affect the transcription and translation of the p85 gene, because the amounts of transcribed mRNA and translated protein of cdaA1 p85 were equivalent to those of wild type p85" (p. 118). The authors conclude the Results section as follows: "Thus, we suppose that the difference in molecular weight between cdaA1 and wild-type p85 was caused by a disorder of post-translational modification mechanisms of p85 in cdaA1 cells." (p. 116). These results demonstrate that p85 is likely not the product of the cdaA1 gene, and that the gene mutated in the cdaA1 strain is more likely to be a protein responsible for the post-translational modification of p85, which is altered in the cdaA1 mutant. (Contributed by J. Frankel, University of Iowa, 2005)
Associated Literature
Ref:11944929: Gonda K, Numata O (2002) p85 binds to G-actin in a Ca(2+)/calmodulin-dependent manner, thus regulating the initiation of cytokinesis in tetrahymena. Biochemical and biophysical research communications 292(4):1098-103
Ref:11942614: Numata O, Gonda K (2001) Determination of division plane and organization of contractile ring in Tetrahymena. Cell structure and function 26(6):593-601
Ref:11129794: Gonda K, Komatsu M, Numata O (2000) Calmodulin and Ca2+/calmodulin-binding proteins are involved in Tetrahymena thermophila phagocytosis. Cell structure and function 25(4):243-51
Ref:10816251: Numata O, Gonda K, Watanabe A, Kurasawa Y (2000) Cytokinesis in Tetrahymena: determination of division plane and organization of contractile ring. Microscopy research and technique 49(2):127-35
Ref:10772759: Numata O, Fujiu K, Gonda K (1999) Macronuclear division and cytokinesis in Tetrahymena. Cell biology international 23(12):849-57
Ref:10523498: Gonda K, Katoh M, Hanyu K, Watanabe Y, Numata O (1999) Ca(2+)/calmodulin and p85 cooperatively regulate an initiation of cytokinesis in Tetrahymena. Journal of cell science 112 ( Pt 21)( ):3619-26
Ref:10527850: Gonda K, Nishibori K, Ohba H, Watanabe A, Numata O (1999) Molecular cloning of the gene for p85 that regulates the initiation of cytokinesis in Tetrahymena. Biochemical and biophysical research communications 264(1):112-8
Ref:7795488: Numata O, Suzuki H, Ohba H, Watanabe Y (1995) The mutant gene product of a Tetrahymena cell-division-arrest mutant cdaA is localized in the accessory structure of specialized basal body close to the division furrow. Zoological science 12(1):133-5
Ref:3536899: Ohba H, Ohmori I, Numata O, Watanabe Y (1986) Purification and immunofluorescence localization of the mutant gene product of a Tetrahymena cdaA1 mutant affecting cell division. Journal of biochemistry 100(3):797-808
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